Floods in Sub-Saharan Africa: Causes, Drivers, and Health Impacts

Understanding the Impact of Flooding in Sub-Saharan Africa

Flooding has become a critical issue affecting various regions around the world, and Sub-Saharan Africa (SSA) is particularly vulnerable due to its unique hydro-climatic conditions and natural fragility. Over the past few decades, the frequency and intensity of precipitation have increased, exacerbating the risk of floods. These events are further intensified by human activities such as urban sprawl, population growth, and changes in land use. The consequences of these floods extend beyond environmental damage, significantly impacting public health and economic stability.

The health effects of flooding are diverse and context-specific, ranging from immediate dangers like drowning and injuries to long-term issues such as waterborne diseases and mental health challenges. In addition, the economic losses caused by flood events in SSA are substantial, highlighting the urgent need for comprehensive flood management strategies.

Governments across the continent must prioritize flood management as part of their national disaster preparedness, response, and mitigation efforts. Floods cannot be addressed in isolation; they must be integrated into urban planning to create resilient and sustainable cities. This approach is essential given the complexity of the African continent, which includes 54 nations with varying geographical and climatic conditions. From equatorial regions to the Sahel and desert areas, rainfall and river flows exhibit high levels of variability across different spatial and temporal scales.

Africa is home to numerous river basins that contribute significantly to total runoff. Flooding is the leading natural environmental disaster globally and remains one of the major challenges in the 21st century. In Kenya, for example, flooding has emerged as the most common meteorological disaster. Globally, the frequency and intensity of floods have increased, causing significant environmental destruction, economic impacts, and disruptions to human activities.

Each year, flooding claims approximately 20,000 lives and affects around 20 million people worldwide. In September 2007, torrential rains and flooding affected 600,000 people in 16 West African countries, with Burkina Faso, Ghana, Senegal, and Niger being the hardest hit. A similar event in 2007 displaced over a million people in Uganda, Ethiopia, Sudan, Burkina Faso, Togo, Mali, and Niger, resulting in more than 500 deaths.

According to the EM-DAT database, floods accounted for 38.7% of all incidents, 6.2% of deaths, and 43.0% of the population affected by all disasters caused by natural hazards between 2000 and 2009. Globally, floods have impacted over 2.8 billion people and caused over 200,000 deaths in recent decades. Between 1995 and 2005, floods affected the lives of 2.3 billion people, making up 47.0% of all weather-related disasters worldwide.

Floods are not a new occurrence in SSA. For instance, Lagos, Nigeria, has experienced flooding since 1947, and it has now become an annually recurring event. In the past decade, the intensity of flooding in SSA has surged. The 2018-2019 southwest Indian Ocean cyclone season led to unprecedented flood damage in Africa. Cyclone Idai, for example, caused devastating flood damage in Mozambique and Zimbabwe, with 602 deaths in Mozambique and 299 in Zimbabwe, along with infrastructure damage worth about $1 billion.

In 2012, 33 out of 36 states in Nigeria were affected by floods, displacing 2.1 million people, killing 363 individuals, and injuring over 18,200. More than 18,000 houses were damaged or destroyed. In April 2022 alone, there were reports of at least eight serious flooding events and twenty deaths in Nigeria and Ghana, despite the global focus on the COVID-19 pandemic.

Floods can be described differently based on location, considering factors such as land surface, hydrology, geomorphology, and duration. The term “flooding” refers to the consequences of a flood, while the flood itself is defined as the condition when water overflows its natural or artificial boundaries, accumulating in low-lying areas.

Since the “long rains” season began in March 2020, more than 13 million people in East Africa have been affected by flooding, with about 981,000 displaced. During the same period, 200 people died due to overflowing rivers and mudslides in Kenya, displacing over 40,000 individuals. For the first time in 120 years, water levels of Lake Victoria reached the highest point, displacing thousands of people and damaging homes, infrastructure, and roads.

Thus, flooding remains the most common environmental natural disaster in SSA, posing a significant threat to achieving sustainable development. The review aims to assess the trends of flooding events and their impact on the health of the human population in SSA. It seeks to describe the causes of floods, flood types, their drivers, and finally, the health impacts of floods. This study analyzes literature and published reports, including grey literature, technical reports, and journal articles. A search was conducted on health databases to gather relevant information.